Is SMTP to a mobile phone a fundamentally flawed way to do this?
Yes. It takes too long and nobody is responsible for making sure it is fast. SMS is better, even though it can also suffer from delays, because somebody is in charge of making sure it is fast. The worst delays I witnessed were over an hour during the terror attacks on London a couple of years ago. We have an SDK http://web21c.bt.com/ that lets people build SMS sending into their applications for event notification, so if you are in Europe, this may be useful. I know other companies have software for sending SMS that works with a PCMCIA GSM card plugged into a computer. If guaranteed turnaround time is important, then becoming an official customer is the best way of communicating those needs. Even better if your supplier is selling you the SMS service specifically for event notification. Outside of having a supplier who offers an SLA on SMS delivery time, I'm not sure that it is wise to rely on SMS for notifying your first responders. --Michael Dillon